In News

    • Recently, XBB.1.16 was found to be the variant behind India’s new COVID spike.


    • Two recombinant lineages of SARS-CoV-2 are currently designated as ‘Variants Under Monitoring’ by the World Health Organization: XBB, a recombinant of Omicron sublineages BA.2.10.1 and BA.2.75, and XBF, a recombinant of BA.5.2.3 and BA.2.75.3 Omicron sublineages.
    • The lineage XBB.1.5, a sublineage of the XBB has functional advantages over currently circulating variants such as increased transmissibility in populations with prior immunity to the virus.
    • Based on preliminary data, there is no evidence to suggest that infections with the XBB.1.16 lineage differ in clinical severity from those caused by other Omicron lineages.It however has a higher risk of reinfection compared to other circulating Omicron lineages.

    Why are viruses Prone to Mutation?

    • Most of the viruses are made up of single strands or RNA. due to the lack of complementary pairing in the strands and RNA being more unstable than DNA leads to higher chances of mutation among viruses. 

    WHO Nomenclature:

    • Variant Under Monitoring (VUM): It is defined as A SARS-CoV-2 variant with genetic changes that are suspected to affect virus characteristics and  shows growth advantage relative to other circulating variants (e.g. growth advantage which can occur globally or in only one WHO region). Evidence of phenotypic impact of these variants is unclear and requires enhanced monitoring and reassessment .
    • Variant of Interest (VOI) : A SARS-CoV-2 variant with genetic changes that are predicted or known to affect virus characteristics such as transmissibility, virulence, antibody evasion, susceptibility to  therapeutics and detectability;
      • VOI are identified to have a growth advantage over other circulating variants in more than one  WHO region with increasing relative prevalence alongside increasing number of cases over time, or other apparent epidemiological impacts to suggest an emerging risk to global public health.
    • Variant of Concern (VOC) : A SARS-CoV-2 variant that meets the definition of a VOI (see above) and, through a risk assessment, conducted by WHO TAG-VE, and determined to be associated with a moderate or high level of confidence, meets at least one of the following criteria when compared with other variants:
      • Detrimental change in clinical disease severity; OR
      • Change in COVID-19 epidemiology causing substantial impact on the ability of health systems to provide care to patients with COVID-19 or other illnesses and therefore requiring major public health interventions; OR
      • Significant decrease in the effectiveness of available vaccines in protecting against severe disease.

    Source: TH